Hydraulic intensifier pumps are widely used in applications requiring the delivery of a high pressure jet of fluid. An intensifier pump includes a pump cylinder, a hydraulic working piston, a product intensifier piston, an inlet for the hydraulic working fluid, an inlet for the product fluid to be pressurized, and an outlet for the pressurized fluid. In operation, lower pressure hydraulic fluid is applied to the comparatively large working piston. The working piston, in turn, drives the smaller intensifier piston. The ratio of the hydraulic and product piston areas is the intensification ratio. The hydraulic pressure is multiplied by the intensification ratio to produce an increase in pressure.
The fluid to be intensified typically is delivered to the intensifier via an inlet check valve from a low pressure fluid supply pump. The fluid supply pump generally is able to generate sufficient pressure to overcome the tension of an internal poppet spring within the check valve, opening the check valve when the intensifier is in the retraction cycle and allowing product fluid to be delivered to the intensifier cylinder. When the piston begins its advance cycle to expel the pressurized fluid, the higher pressure of the intensified product fluid overcomes the lower supply pressure, closing the inlet check valve and thereby preventing backflow of the intensified fluid into the low pressure supply side of the pump. Many intensifier systems incorporate two or more single acting, single ended intensifier pumps, or two double intensifier pumps, that advance and retract on an alternating basis to provide a substantially continuous fluid jet. When one product intensifier piston retracts, the other advances. The relative timing of the advance and retraction cycles is carefully controlled to provide a substantially constant fluid pressure. Nevertheless, intensifier systems incorporating multiple single or double-acting intensifier pumps typically exhibit minor pressure fluctuations.
For industrial applications requiring precise fluid delivery, pressure fluctuation can be highly undesirable. For example, in processing of dispersions, emulsions, liposomes, and the like, the total amount of work, or energy, being applied is a function of both the mechanical power, or shear, and the time the product is in the shear zone. Further, in order to effectively process dispersions, the energy level must be sufficiently high and uniform to disperse agglomerate structure. A gradient of energy levels being applied to a dispersion, a result of processes having pulsation, will result in some of the product being subjected to insufficient processing. Continued processing of the product, under conditions where pulsations exist, cannot compensate for the gradient of energy levels that is less than the energy level required. Other applications that suffer from pulsation include the processing and pumping of coating solutions to a coating process such as a dual layer coating die.